使用vb.NET / asmx / Mysql的奇怪行为

Question

我正在开发一个基于Windows的VB.NET应用程序，它可以作为后端和Web服务器使用mysql。我使用Web服务（asmx）连接到数据库，所有操作都运行良好。有时对于某些SELECT查询，它不会产生任何结果（也没有错误），对于同一查询，它会在一小时后或第二天生成结果。由于这种行为，我找不到任何错误的标签并继续该项目。

如果你能让我知道发生了什么，请提前致谢

代码在

之下

<SoapHeader("Authentication")> _
<WebMethod(Description:="Get the result from sql query - Returns a Dataset")> _
Public Function ExecuteQuery(ByVal strQuery As String) As DataSet

    Dim ds As DataSet = New DataSet 'create a DataSet to hold the results
    If decryptString(Authentication.Username) = "bla bla" AndAlso decryptString(Authentication.Password) = "bla blah" Then

        Try

            'create a MySqlCommand to represent the query
            If sqlConn.State = ConnectionState.Closed Then
                sqlConn = New MySqlConnection(conStr)
                sqlConn.Open()
            End If

            Dim sqlcmd As MySqlCommand = sqlConn.CreateCommand()
            sqlcmd.CommandType = CommandType.Text
            sqlcmd.CommandText = strQuery

            'create a MySqlDataAdapter object
            Dim sqlDa As MySqlDataAdapter = New MySqlDataAdapter
            sqlDa.SelectCommand = sqlcmd

            Try
                'fill the DataSet using the DataAdapter
                sqlDa.Fill(ds, "Results")
            Catch ex As Exception
                Throw New ApplicationException("Error-luckie's server 1 " & ex.Message)
            End Try

        Catch ex As Exception
            Throw New ApplicationException("Error-luckie's server 2 " & ex.Message)
        Finally
            sqlConn.Close()
            sqlConn.Dispose()
        End Try

    End If
    Return ds

End Function